New treatments for Irritable Bowel Syndrome (IBS)

One of the possible mechanisms involved in IBS is gut dysbiosis, which refers to changes in the balance of the gut microbiota —the community of microorganisms living in the intestine.

Faecal microbiota transplantation (FMT) involves transferring faecal microbiota from a healthy person’s processed stool sample into the intestinal tract of a person with a specific medical condition. Its aim is to restore a healthy microbial balance.

Currently, FMT is an established treatment only for recurrent Clostridioides difficile infection, where it has been shown to be highly effective.

Several studies have investigated whether FMT can improve symptoms in people with IBS, and some findings suggest that it may benefit certain patients. However, the evidence remains highly variable and inconclusive. For this reason, FMT is not recommended as a routine treatment for IBS and its use is limited to research settings or selected cases.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive technique that is already used in the management of some neurological and psychiatric conditions. It uses a small device to deliver low-intensity electrical impulses to an area of the ear known as the concha. This part of the ear contains nerve fibres connected to the vagus nerve, allowing the nerve to be stimulated externally.

The vagus nerve plays an important role in communication between the gut and the brain, as it helps regulate many functions of the digestive system. For this reason, stimulating the vagus nerve could potentially become a useful approach for conditions such as IBS.

Early studies suggest that taVNS may improve symptoms in some patients, particularly those with IBS with constipation (IBS-C), and may have a positive effect on rectal function and the gut microbiota. However, this is still an emerging area of research and taVNS is not currently part of standard IBS treatment

Another factor that may play a role in IBS is mild, persistent inflammation in the gut. This is known as low-grade inflammation. It is a type of inflammation that does not cause symptoms as severe as those associated with an infection, but which may nevertheless affect the normal functioning of the digestive system. Immune cells in the gut, including mast cells, contribute to this response.

Mast cells are immune cells found throughout the digestive tract. When activated, they release substances such as histamine. These substances can influence bowel movements, increase sensitivity in the gut and contribute to abdominal pain. Increased mast cell activity may therefore contribute to IBS symptoms. Mast cells are also involved in severe allergic reactions, such as anaphylaxis.

For this reason, some studies have explored treatments aimed at regulating mast cell activity, particularly in IBS with diarrhoea (IBS-D). Treatments that have been studied include:

• Antihistamines, which block the effects of histamine.
• Cromoglicate, which helps reduce the release of inflammatory substances from mast cells.

Although the early findings are promising, these treatments are not yet part of standard IBS management. Further research is needed to establish their potential benefits and clinical usefulness.